Today, June 4, is the most important date in 20th century history. On this date, Japan lost World War II to the US, and Germany lost World War II. Without the events of June 4, we probably wouldn't be speaking Japanese in San Francisco, but it is likely that they would be speaking German in London.
On June 4, 1942, Japan lost WW2 in the battle of Midway. In the span of 20 minutes, a squadron of American dive bombers stumbled upon the Japanese fleet preparing to invade Midway Island and put three of four Japanese aircraft carriers out of commission. Later in the day, the fourth was destroyed. Japan couldn't recover. It took three more difficult years to drive Imperial Japan to surrender, including the worst of war on both sides (kamikazis, Iwo Jima and Okinawa, fire-bombing cities, the atomic bombs), but the fate of the Japanese was determined. With the sinking of the Akagi, Kaga, Soryu, and Hiryu, they could no longer win the war.
There wasn't a corresponding decisive battle in the European Theater. Some might argue that the first six hours of the Normandy Invasion signaled the end of the war, but by then the industrial might of the Allies (OK, "America") had already won the war. The European Theater was more a case of the Germans losing the war than the Allies winning.
In the spring of 1940, a large part of the British army was in Belgium to defend France from the expected invasion from Germany. The German attack began on May 11, and by May 22 it was evident the British were being overwhelmed. The British had been driven back to a small perimeter around the French port of Dunkirk, and they were hard-pressed to hold off the superiour German forces. The British began an evacuation that, for a variety of reasons, wasn't working. However, on May 29, Hitler stopped the German panzer attacks and gave the infantry and air force the job of destroying the British. This gave the English time to mobilize a "flotilla of fishing boats, lifeboats, paddle steamers, and yachts" to rescue the more than 300,000 British and French troops trapped around Dunkirk. By June 4, the evacuation was complete.
Interestingly, as Garrison Keillor points out in today's Writers' Almanac or (click here for written version), it was the decision of Winston Churchill to treat the returning servicemen as heros rather than as a defeated army that lead to the victory over Germany five years later.
Can we learn anything from these events 60+ years later?
If you listen to the the full reading of the Writer's Almanac, you'll hear the Poem of the Day. Some of us think that if it doesn't rhyme and isn't written in meter, it's just prose in very short paragraphs, but I'll cut the poem "Pulling Up Beside My Husband at the Stoplight" some slack.